Positioning for Search and Rescue in GPS-Denied Area by Distributed WiFi RSS-Based DoA Modules

Environmental factors affect the Received Signal Strength (RSS) so the received data exhibit random propagation characteristics, such as fading and shadowing effects. This study proposes a Direction of Arrival (DoA) module for the Search and Rescue (SaR) or anti-drone applications, which uses patch antennas and a rat-race coupler as the receivers. An angular estimation is presented for WiFi positioning, using optimally placed DoA antennas and a pseudo-inverse algorithm. The experiment is performed in a university campus with the device under test (DUT) as the transmitter. Using four DoA antennas as receivers at the corners of a 100m $\times 100\text{m}$ region, the mean positioning deviation is about 2m, which is 2% of the region. The confidence range for the estimated positions is also calculated.